1. Field of the Invention
The present invention relates generally to electric power generators. More specifically, the present invention relates to permanent magnet electric generators.
2. Description of the Related Art
The basic construction of electric power generators has not changed significantly over the years, taking the form of a rotating a magnetic within a ring of wound wire. Improvements in construction for increasing the efficiency of the generator have been the object of much research and innovation.
U.S. Pat. No. 1,726,042, issued to Reis in 1929, discloses a generator having a rotor having permanent magnets. These magnets are at least partially encircled with ferromagnetic metal to control eddy currents and to increase permeability of local portions of the magnetic field.
U.S. Pat. No. 5,447,758, issued to Shimizu in 1985, discloses a cylindrical permanent magnet having at least eight poles.
U.S. Pat. No. 4,780,634, issued to Masterman in 1988, discloses an electric generator having a rotor, a plurality of pole sections spaced around the circumference of a rotor core at a constant pole section pitch, a toothed stator (a stationary part in a machine in or about which a rotor revolves), two or more independent windings, and a plurality of bridge members to separate adjacent windings.
Japanese Patent Document No. 3-82348, published in 1991, discloses a rotor for a generator wherein the magnetic field is augmented by a second series of magnets placed inside an external ring of primary magnets.
U.S. Pat. No. 5,457,870, issued to Canders in 1995, discloses an improved rotor for electric machines having a high rotational speed. The rotor described in the '870 patent has a rotor core and a rotor shell comprising a binding made of fiber-reinforced plastics radially supporting the rotor core.
Advances in rotor and stator design have been disclosed in several devices. U.S. Pat. No. 6,487,770, issued to Bernauer et al. in 2002, discloses rotors or stators cut out from rolled sheet metal with a predominant magnetic direction and which are stacked to form a rotor or stator lamination bundle. Furthermore, a rotating electrical machine stator having improved heat dissipation due to the insertion of a silicon rubber sheet between a stator core and the stator windings is disclosed by U.S. Pat. No. 6,525,437, issued to Ozawa et al. in 2003.
High efficiency generators for powering motor vehicles are described in several devices and include: U.S. Pat. No. 3,845,835, issued to Earl W. Petit in 1974, and U.S. Pat. No. 4,348,628, issued to Loucks in 1982.
W.I.P.O Patent No. 03/012955, published in 2003, discloses a stator assembly for an electric rotating machine having a plurality of annular laminated core sections with an extending coolant duct provides increased cooling efficiency.
U.S. Pat. No. 5,608,279, issued to Murray (the present inventor) in 1997, discloses a permanent magnet generator with an improved rotor and stator. The '279 patent discloses a rotor having a pair of diametrically opposed magnet groups, each group consisting of curved magnets of unequal flux strength. Furthermore, at any one time only one set of magnets and stators is in alignment.
Japanese Patent No. 2002-272072, published in 2002, discloses a DC generator having a rotor having multiple two-pole magnets aligned along the rotor. A single stator is disclosed having armature windings around an integral number of three poles. The armatures are individually provided with a rectifier allowing the DC outputs of each winding to be obtained without need for a commutator or a brush.
U.S. Patent Application Publication 2002/0195900, published in 2002, shows a stator construction that utilizes a single piece of metal. In addition, W.I.P.O. Patent No. 02/099950, published in 2002, describes a rotor with magnets mounted at even intervals around the rotor.
The technology utilized in motors is similar to that of electric generators and includes a rotor and stationary windings. U.S. Pat. No. 4,751,415, issued to Kitamori et al. in 1988, discloses a brushless DC motor comprising a stator with plural exciting windings and a rotor made of a permanent magnet provided with a compensation winding wound in the stator and compensation magnetic poles disposed on the rotor. U.S. Pat. No. 4,237,397, issued to Mohr et al. in 1980, discloses a permanent magnet stator having two permanent magnet segments formed in an arc, each segment further comprising two subsegments.
U.S. Pat. No. 4,112,230, issued to Mohr in 1978, discloses an elongated magnet structure having zones of different magnetic properties for use in electric dynamos.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus an improved power unit solving the aforementioned problems is desired.